I've been living in Orlando for the last couple years. The running scene downtown isn't terrible, but it's no match for what you're probably used to in the way of clubs in Boston. Running in the city itself is completely a cobblestones and pavement phenomenon, but there are some very nice (and surprisingly hilly) runs in Clermont, about 30 minutes away. There are a couple groups in Downtown Orlado that hold weekly track sessions and tempo runs. Very, very nice people.
The triathlon scene overwhelms the running scene, although Track Shack does put on a very nice 5k/8k/10k Grand Prix series from August to March every year. Nice prize money, and very well-organized events. Mid- to high- 15's wins the 5k's. Again, this is a far cry from the competitive atmosphere you'll find in Boston; Track Shack's emphasis is "citizen racing," although there are some very talented former collegiate runners down here.
You'll have to travel back north for any all-comers track meets. There's just none of that to be had down here. Lastly, the heat and humidity aren't terrible. You'll have to go early if you want to do anything long over the summer, as well as place water on your course. But October to April are simply a dream. Wonderful change of pace for a native Chicagoan to be able to run in t-shirt and shorts in January.
Please feel free to e-mail if I can be of any further assistance.
DT